I posted this tutorial some time ago.

Yeah, grates are textures, just look for 'grate' and you'll find some. It's recommended to make the brush completely textured with nodraw and only texture with the grate texture only the face/s that the player will see. And do not forget to surrround them with frames as the previous poster said. For frames you do have 2 options: models and brushes. If you want the models search for "squarebeam", for making it out of brushes, search for 'plasticwall' as the previous post suggested, but depending on the look you are looking for, check out if 'track' could fit too.

Remember to tie your brushes (grate and frames) to func_details or func_brushes to avoid that they create visleaves

In which case, yes, it's made from brushes and a prop_dynamic for the panel. "plasticwall" is the border (4 units wide) and the center is "metalgrate018". All tied to a func_brush, of course. I, personally, really like these grating arms and I try to use them extensively.